1. Field of the Invention
The present invention relates to a film supplying apparatus in a film developing system of a leader sheet conveying type. The present invention also relates to a photographic film processing apparatus for automatically implementing a series of processes comprising developing the photographic film strip, printing an image from a developed film onto photographic printing paper, and developing the photographic printing paper.
2. Discussion of the Related Art
Generally, when an undeveloped film strip wound in a cartridge is developed in a film developing system of a leader sheet conveying type, a tapered tongue end portion of the film strip is drawn out of the cartridge to be cut off, and, after a leader sheet is coupled with the end portion of the film strip, the film strip with the leader sheet in front is transported to a film developing section.
The leader sheet is made of a flexible plastic sheet and has a row of perforations for feeding the leader sheet. Each leader sheet is formed with the perforations at equal intervals and they are engageable with sprockets in the film developing section.
The leader sheet is generally coupled with the film strip by sticking a splicing tape on the film strip and the leader sheet. But the splicing tape demands time to attach it and time to peel it off after the film is developed. Further the tape presents an additional inconvenience in that a special working table is necessary for coupling the film strip to the leader sheet because the film strip must be precisely connected to a predetermined position of the leader sheet. Another problem is that the splicing tape is not economical because the tape can not be used repeatedly.
To solve the problems mentioned above, the assignee of the present invention has already proposed a coupling structure for a leader sheet and a film strip as shown in FIG. 15 (related to Japanese Patent Application No. 230253 of 1995).
In the coupling structure a first insert slot 1 and a second insert slot 2 are formed on a leader sheet L. The leader sheet L has a row of perforations h for feeding the leader sheet. A coupler tongue 3 is formed so as to extend across a first insert slot 1 in the transporting direction of the leader sheet. The front end portion of the coupler tongue 3 is located over one side of the slot 1 and the rear end portion of the coupler tongue 3 is supported by a peripheral portion of the first insert slot 1. The end portion of the film strip F is inserted through a second insert slot 2 into the first insert slot 1 and thereby the coupler tongue 3 engages a coupling hole 4 arranged at the end portion of the film strip F.
In the coupling structure for the leader sheet and the film strip, the film strip is allowed to be easily and firmly connected to the leader sheet at a predetermined position.
Heretofore is also well known to use a photographic film processing apparatus in which a photographic film is developed in a film developing section, and the developed film is sent into a printing section located next to the film developing section. The images in the developed film are then printed onto photographic printing paper and the photographic printing paper is then developed.
When the photographic film is developed in the photographic film processing apparatus mentioned above, the photographic film may be coupled to flexible leader sheet and led and conveyed by the leader sheet through the film developing section to be developed. On the other hand, in the printing process, only the developed negative film is sent into the printing section for print processing.
Therefore between the developing section and the printing section, the photographic film is separated from the leader sheet and only then is the film strip sent into the printing section.